In wafer fabrication, a probe card with high performance is required to perform a wafer test prior to the wafer saw so as to test the quality of dies on the wafer, as disclosed in the prior art such as U.S. Pat. No. 6,292,005 as well as Taiwan patent No. TW460703. A precise contacting apparatus is located on the probe card to make contact with the wafer under test, conduct circuits, and perform electric test.
Refer to FIG. 1A. A schematic view of a wafer test system is illustrated. A control system 10 emits a test signal and passes it to a tester 12 as known by those skilled in the art. A motherboard 15 and a ZIF (Zero Insertion Force) female plug connector 17 are equipped on the tester 12. The ZIF female plug connector 17 is to be connected with the ZIF connector 18 so as to transmit the test signal to the probe card 19. U.S. Pat. Nos. 6,184,698, 6,398,570, 6,478,596 as well as Taiwan Patent No. TW475984 have disclosed a method for connecting the ZIF female plug connector 17 with the ZIF connector 18. The probe card 19 is provided with probe pins 20 on its bottom for electrically connecting the ZIF connectors 18. A prober loads the wafer under test 21 onto the moving table 22 so that the wafer 21 can be contacted with the probe pins 20 on the bottom of the probe card 19 via the movement of the moving table 22 to perform the test as well as to send the test signal back to the control system 10.
Refer to FIG. 1B. A conventional connection mode of the ZIF connector 18 and the probe card 19 is shown. A rivet 201 directly passes through the ZIF connector 18 and the probe card 19, and thus the ZIF connector 18 is riveted on the upper surface of the probe card 19. A plurality of golden fingers 202 are disposed on each of two sides of the ZIF connectors 18 so as to transmit signals to the ZIF female plug connector 17. In addition, the golden fingers 202 are extended under the ZIF connector 18 and extended outwardly to form a radial shape so as to make contact with pads on the probe card 19 (not shown) for receiving signals. In the conventional rivet-connection mode, the swaging force needs to be precisely controlled in strength and direction when swaging the rivet 201. As a result, a certain gap A and a certain predetermined force can be maintained after all the golden fingers 202 have the contact with the pad on the probe card 19, thereby the impedance match can be fixed to obtain the stable test signals. During the wafer testing process, the ZIF connectors 18 must be capable of sustaining the repeatedly plugged and unplugged operations from the female plug connector 17. After a while, the golden fingers 202 will be worn out, and it will change both the gap A and the predetermined force to cause bad connections between the pad portion of the probe card 19 and the golden fingers 202, thereby the test result will be affected. Then, the probe card will have to be replaced for maintenance.
Refer to FIG. 1C. A schematic view of another conventional ZIF connector structure from U.S. Pat. No. 6,642,729 is shown. Fixed pins (i.e. rivets) 1251 and 1253 are disposed under the ZIF connectors so that the ZIF connectors can be connected to the probe card and affixed thereon.
Refer to FIG. 1D. A top view of the ZIF connector 18 affixed on the probe card 19 is shown. In this example, there are sixty four ZIF connectors 18 affixed on the probe card 19. It is to be noted that when the probe card 19 proceeds to the wafer test, if the abnormality occurs in the gap or the predetermined force between some golden finger of the ZIF connectors 18 and the probe card 19, the whole probe card 19 has to be removed from the testing system. The ZIF connector 18 needs to be replaced and the gap A and the predetermined force need to be re-adjusted. During the steps of replacing the ZIF connector 18, a rivet head needs to be peeled off by using a sharp knife so that the rivet can be removed; however, if force is carelessly applied, the ZIF connector 18 can be easily damaged, or worse, the probe card 19 can be damaged. The structure of the probe card 19 is very complex. General speaking, the probe card 19 is of multiple layers, usually more than twelve layers. The pitch between the pads thereon is very small and needs to be reworked at a semiconductor level so that the price is extremely expensive. The cost becomes very high due to replacing the whole probe card 19, when damage is caused by adjusting or detaching a ZIF connector 18. Therefore, what is urgently needed is to provide a simple and effective approach to connecting, replacing and adjusting the ZIF connector and the probe card.